This application claims the benefit of Belgian Application No. 2001/0269 filed Apr. 20, 2001.
The invention relates to a face-to-face weaving machine with face-to-face shed forming, a twister device being provided which is situated between weaving frames mutually provided with a free space, and a weaving reed and the twister device being provided with means for positioning a first series of warp threads in waving means, means to wave the first series of warp threads and means to cause a second series of warp threads to move up and down, the said means to cause a second series of warp threads to move up and down, being driven by a driving device provided with a casing.
The invention further relates to a twister device for a face-to-face weaving machine with face-to-face shed forming, comprising means for positioning warp threads in waving means, means for waving warp threads and means to cause warp threads to move up and down and which are driven by a driving device provided with a casing.
In EP 0 152 956 a twister device for weaving machines is described, preferably for double rapier weaving machines for face-to-face velvet or carpets in order to obtain edges, which are free from fraying, the twister being provided with one or more parallelogram linkage systems with vertical sides, the front of which is held in a vertical position, whilst the adjoining bars may turn back and fro around hinged points at the angles of the parallelogram, so that the thread-guides can move an up and down.
This twister device is installed on either side of the weaving machine starting from the back traverse between the supporting beams for the weaving frames towards the fabric. The disadvantage of this construction is, that when performing a new heddling of the warp threads for weaving another fabric the weaving frames must be removed from the weaving machine, because of which the twister device must be removed. After having placed the new weaving frames a re-installation and new heddling of the twister device is a very time-consuming job.
The purpose of the invention is to provide a face-to-face weaving machine with face-to-face shed forming, provided with a twister device, not having the disadvantages mentioned above and further to provide a twister device for face-to-face weaving machines with face-to-face shed forming not having the disadvantages mentioned above.
On the one hand this purpose is attained by providing a face-to-face weaving machine with face-to-face shed forming on which a twister device is provided, situated between the weaving frames, mutually provided with free space and a weaving reed and the twister device being provided with means for positioning a first series of warp threads in waving means, means to wave the first series of warp threads and means to cause a second series of warp threads to move up and down and said means to cause a second series of warp threads to move up and down being driven by a driving device provided with a casing, and said means for positioning a first series of warp threads in waving means, said means to wave the first series of warp threads, and said means to make a second series of warp threads to move up and down being attached to vertical sliding rods, being guided in a guiding channel forming one piece with the casing of the driving device and said means for positioning a first series of warp threads moving in the free space between the weaving frames.
An additional advantage of this system is that the positioning eyes can move up and down within the free space of the weaving frames.
In a preferred embodiment of the face-to-face weaving machine with face-to-face shed forming according to the invention the driving device is attached to the front traverse of the face-to-face weaving machine.
In a more specific preferred embodiment of the face-to-face weaving machine according to the invention, the position of the driving device on the front traverse of the face-to-face weaving machine can be adjusted in the weft-direction.
On the other hand, this purpose is attained by providing a twister device for a face-to-face weaving machine with face-to-face shed forming, comprising means for positioning a first series of warp threads in waving means, means to wave the first series of warp threads and means to cause a second series of warp threads to move up and down, said means to cause a second series of warp threads to move up and down being driven by a driving device provided with a casing, and said means for positioning a first series of warp threads in waving means, said means to wave the first series of warp threads (101), and said means to cause a second series of warp threads to move up and down being attached to vertical sliding rods, being guided in a guiding channel forming one piece with the casing of the driving device.
Because of the very narrow design of the guiding channel and the sliding rods in the warp-direction and the weft-direction, the space taken up between the weaving reed and the weaving frames is kept very small, and also the loss in fabric width is kept extremely small. The weaving frames only need to be shifted back partly opposite the space in which the slot-plates and needle sets are working.
In a preferred embodiment of the twister device the mutual distance of said means for positioning a first series of warp threads in waving means, said means to wave the first series of warp threads and said means to cause a second series of warp threads to move up and down is adaptable to the pile height by adjusting the mutual distance between the top and bottom fabrics via a slot-connection.
In a particularly advantageous embodiment of the twister device the driving device comprises a driving shaft which is rotatable with respect to a driving means of the driving device and can be connected to that driving means in an adjustable position.
The advantage of this construction is that a different synchronisation can be obtained on the left and right sides of the weaving machine.
In a still more particularly advantageous embodiment of the twister device said driving shaft is clampable in a hollow shaft of the driving means.
In a most particularly advantageous embodiment of the twister device the driving device comprises a cam with a hollow shaft in which the driving shaft can be clamped in a certain position by means of a clamping sleeve.
This invention is further clarified in the following non-restrictive description of a preferred embodiment of a face-to-face weaving machine with face-to-face shed forming, provided with a twister device and a twister device for a face-to-face weaving machine with face-to-face shed forming according to the invention.